/* This file is part of test microkernel for OpenRISC 1000. */
/* (C) 2001 Simon Srot, srot@opencores.org */

#include "support.h"
#include "spr_defs.h"
#include "int.h"

/* Interrupt handlers table */
struct ihnd int_handlers[MAX_INT_HANDLERS];

/* Initialize routine */
int int_init(void) {
	int i;
	
	// initialize Interrupt handler table
	for(i = 0; i < MAX_INT_HANDLERS; i++) {
		int_handlers[i].handler = 0;
		int_handlers[i].arg = 0;
	}
	
	// mask all interrupt
	mtspr(SPR_PICMR, 0x00000000);

	// set OR1200 to accept exceptions (external interrupt enable)
	mtspr(SPR_SR, mfspr(SPR_SR) | SPR_SR_IEE);

	return 0;
}

/* Add interrupt handler */ 
int int_add(unsigned long vect, void (* handler)(void *), void *arg) {
	if(vect >= MAX_INT_HANDLERS)
		return -1;

	int_handlers[vect].handler = handler;
	int_handlers[vect].arg = arg;

	mtspr(SPR_PICMR, mfspr(SPR_PICMR) | (0x00000001L << vect));

	return 0;
}

/* Disable interrupt */ 
int int_disable(unsigned long vect) {
	if(vect >= MAX_INT_HANDLERS)
		return -1;

	mtspr(SPR_PICMR, mfspr(SPR_PICMR) & ~(0x00000001L << vect));

	return 0;
}

/* Enable interrupt */ 
int int_enable(unsigned long vect) {
	if(vect >= MAX_INT_HANDLERS)
		return -1;

	mtspr(SPR_PICMR, mfspr(SPR_PICMR) | (0x00000001L << vect));

	return 0;
}

/* Main interrupt handler */
void int_main(void) {
	unsigned long picsr = mfspr(SPR_PICSR);   // process only the interrupts asserted at signal catch, ignore all during process
	unsigned long i = 0;

	while(i < 32) {
		if((picsr & (0x01L << i)) && (int_handlers[i].handler != 0)) {
			(*int_handlers[i].handler)(int_handlers[i].arg); 
		}
		i++;
	}

	mtspr(SPR_PICSR, 0);	// clear interrupt status: all modules have level interrupts, which have to be cleared by software,
}                          	// thus this is safe, since non processed interrupts will get re-asserted soon enough

